1. Field of the Invention
The present invention provides an anesthesia delivery apparatus. More specifically, the present invention comprises an electronic anesthesia delivery apparatus for controlling delivery of at least two anesthetic agents from at least two respective diffusers to a patient.
2. Description of the Related Art
Standard anesthesia delivery machines utilize a plurality of mechanical components to deliver a measured amount of anesthesia to a patient, for example, an animal. Many of these standard devices include an oxygen flow meter, a pressure gauge, and a vaporizer. Such vaporizers typically include a canister housing an anesthetic agent and a wicking material. As the wicking material absorbs the anesthetic agent, oxygen flows by the wicking material and vaporizes the anesthetic agent molecules for delivery to the patient. In order to vary the delivery percentage of drug to the user, an oxygen control valve is opened or closed in order to vary the amount of oxygen flowing past the wicking material, thus varying the percentage of drug delivered to the patient. A mechanical thermostat regulates the division of oxygen flow within the vaporizer in order to compensate for changes in temperature of the anesthetic agent due to the vaporizing process, or due to change in room temperature
One problem associated with the above mentioned traditional vaporizers is that being mechanical, the vaporizer loses accuracy due to wear of the internal mechanical thermostats and loss of efficiency of the wicking material. Therefore the vaporizer must be periodically removed and sent to a repair facility for overall. Another problem is the specifications for vaporizers on the market today. Most have accuracy of +/−15% of the percentage flow rate indicated and others have accuracy specification of +/−20% of the indicated percentage flow rate of anesthesia. Yet another problem is their up-front expense and the inability to be easily converted to new drug types. In order to convert to a new drug type, the wicking material must be replaced requiring removal of the canister from the machine. Such design is not cost effective. It would be preferable to design a device wherein anesthetic agent may be replaced rather than requiring replacement of the entire canister and the wicking material.
Another weakness of the traditional vaporizers is their percentage of anesthesia output with respect to flow over a time period. Initially the output percentage is low at start up flows and increases to the output dial setting then holds steady at about +/−15 to 20% (percent) of a dial setting through oxygen flows of up to about 7 to 10 liters of flow. After that point the output percentage decreases due to the higher flowrates of oxygen flowing through the vaporizer.
Another problem is that physicians must manually operate mechanical valves and dials on anesthesia machines. Typically, these valves must be operated at different locations of the anesthesia machine. This is difficult and requires the physician or assistant to look to different locations of the delivery apparatus to make adjustments. Further, the physician or assistant must try to compensate for temperature and flows based on information provided by the gauges. It would be preferable to design a device which may be controlled by a single interface and which compensates for operating conditions electronically.
Given the foregoing, it will be appreciated that an apparatus is required which overcomes the aforementioned difficulties and deficiencies.